1. Field of the Invention
The present invention relates to a method of forming a metal line and a method of manufacturing a display substrate having the metal line. More particularly, the present invention relates to a method of forming a metal line, which is capable of decreasing a manufacturing cost, and a method of manufacturing a display substrate having the metal line.
2. Description of the Related Art
A liquid crystal display (“LCD”) device, in general, includes a display substrate, an opposite substrate, and a liquid crystal layer interposed between the display substrate and the opposite substrate. The liquid crystal layer includes liquid crystals having anisotropic dielectric constant. The liquid crystals vary arrangement in response to an electric field applied thereto, and a light transmittance of the liquid crystal layer is changed, thereby displaying an image.
The display substrate includes a plurality of gate lines that are substantially in parallel with each other and a plurality of source lines that are substantially in parallel with each other. The source lines cross the gate lines. Pixels, are defined by the gate and source lines, and are arranged in a matrix configuration. A switching element and a pixel electrode are formed in each of the pixels. The switching element applies a pixel voltage to the pixel electrode.
The switching element includes a gate electrode, a channel layer, a source electrode, and a drain electrode. The gate electrode is electrically connected to one of the gate lines. The channel layer is overlapped with the gate electrode, and is electrically insulated from the gate electrode. The source electrode is electrically connected to one of the source lines and the channel layer. The drain electrode is spaced apart from the source electrode, and is electrically connected to the channel layer.
When a screen size and a resolution of the LCD device are increased, the display substrate requires a line having lower resistance. The line includes aluminum or aluminum alloy having low resistivity. However, the aluminum reacts with the pixel electrode, and diffuses into silicon. Therefore, when the line includes the aluminum or the aluminum alloy, the line has a multi-layered structure. However, the multi-layered structure increases a manufacturing cost of the LCD device.